1. Field
The present disclosure is directed to a method and apparatus for adaptive data rate determination in a wireless communication network. More particularly, the present disclosure is directed to adaptive aggressive reverse rate transition for enhanced throughput performance in wireless communication systems.
2. Introduction
Wireless communication devices used in today's society include mobile phones, personal digital assistants, portable computers, gaming devices, and various other electronic communication devices. A wireless communication device communicates wireless signals over a wireless network, such as a Radio Access Network (RAN), such as over a Code Division Multiple Access (CDMA) network, a Time Division Multiple Access (TDMA) network, a Long Term Evolution (LTE) network, a CDMA2000 network, such as a Single Carrier Radio Transmission Technology (1xRTT) network, or any other wireless network.
A wireless communication device operates at different data rates. To operate at a given data rate, the wireless communication device requests the given data rate from the RAN. The wireless communication device determines the given data rate based on the supplemental channel cost and available power budget on the device.
If the device has sufficient power for a given radio condition, it will make the request for a maximum rate allocation. However, if the device transmit power increases due to shadowing or higher path loss, the available power budget will be lower, and therefore the requested data rate should be also lower. For example, if the device transmit power increases due to a large average fade duration (Tz) or higher path loss, the available power budget will be lower, and therefore the requested data rate will degrade and should be lower. The Average Fade Duration (Tz) is the average time that the signal envelope stays below a given target level Z. This target level Z is the power level required for a given performance metric such as bit error rate, Frame error rate, or other performance metric.
However, some devices do not follow this rate allocation principle. As a result, the devices always make the request for maximum data rate regardless of radio conditions, transmit power budget, and other active mobiles in the network. Additionally, new form factors may impact the antenna performance and therefore reduce a device's antenna total radiated power, which adversely impacts the rate request algorithm explained before.
For example, devices make a blind maximum request by always requesting the maximum data rate. Unfortunately, this approach adversely affects the devices performance because it generates power amplifier splatter, increases noise rise, which affects sector capacity, and also increases a packet error rate.
Thus, there is a need for an adaptive data rate determination in a wireless communication network.